词条 | Emmett Chappelle |
释义 |
Emmett W. Chappelle (born 24 October 1925 in Phoenix, Arizona) is an African-American scientist who made valuable contributions in the fields of medicine, philanthropy, food science, and Astrochemistry. His achievements led to his induction into to the National Inventors Hall of Fame for his work on Bio-luminescence, in 2007. Being honored as one of the 100 most distinguished African American scientists of the 20th Century, he is also a member of the American Chemical Society, the American Society of Biochemistry and Molecular Biology, the American Society of Photobiology, the American Society of Microbiology, and the American Society of Black Chemists. Early lifeIn 1924, Emmett Chappelle was birthed by his parents, Viola Chappelle and Isom Chappelle, who were known to grow cotton and herd cattle on their farm. Born into segregation, Chappelle was required to attend a segregated school known as Phoenix Union Colored High School in Phoenix, AZ, where he was the top graduate of his senior class of 25 students. Upon graduation, in 1942, Emmett enlisted in the army where he was able to take some engineering courses before being assigned to the 92nd infantry that was stationed in Italy. During his time in the service, he suffered from two non-fatal wounds in action. After his return from Italy, in 1946, he began to attend Phoenix College where he studied electrical engineering and received an A.A degree before he redirected his focus and career towards the sciences. Career and important discoveriesIn 1950, Chappelle received a Bachelor's of Science degree in Biochemistry from the University of California, Berkeley, then served as an instructor of biochemistry at Meharry Medical College in Nashville, Tennessee, from 1950 to 1953, without graduate training. He then left Tennessee to continue his education at the University of Washington where he received his masters degree, also in Biochemistry. From 1955 to 1958, he worked as a research associate at Stanford University where he was also appointed as a scientist and biochemist for the Research Institute of Advanced Studies until 1963. Then, in 1958, Chappelle joined the Research Institute in Baltimore, a division of the Martin Marietta Corporation that was famous for designing airplanes and spacecraft. There, Chappelle made a major discovery that has largely contributed to the knowledge of bacteria, cyanobacteria, and other single-celled organisms around the world. He discovered that even single-celled organisms such as algae, are photosynthetic, meaning they are able to convert carbon dioxide to oxygen. This ability to photosynthesize atmospheric carbon dioxide to oxygen is characteristic of all plants that is the opposite process of cellular respiration, that all animals and non-photosynthetic organism rely on to sustain life. Both photosynthesis and cellular respiration are used to create energy that is used to carry out all functions in an organism. Since humans rely on cellular respiration, the conversion of oxygen to carbon dioxide, and algae relies on photosynthesis, the conversion of carbon dioxide to oxygen, astronauts were able to survive in space with a constant renewal of oxygen. This knowledge was not only beneficial to astronauts because it allowed scientists to develop a method for creating clean oxygen for astronauts in space, but it also provided them with a safe food source that is capable of reproducing in space. In 1963, Chappelle went to work at Hazelton Laboratories, now known as Covance Inc., as a biochemist but later joined the National Aeronautics and Space Administration (NASA) as an exobiologist and astrochemist, in 1966. As an exobiologist and astrochemist of NASA, someone who focuses towards the search for extraterrestrial life and studies the chemistry of astronomical objects, he worked on the Viking Spacecraft and helped develop instruments to collect and scrape soil from the surface of Mars. However, he was most well known for his work on biolumenescence. In 1977 he was moved to the Goddard Space Flight Center in Greenbelt, Maryland, as a remote sensing scientist, studying natural systems to improve environmental management. Some of Chappelle's most interesting work was in the area of luminescence, which is light without heat. While designing instruments for the Mars Viking spacecraft, he became interested in bio luminescence, which is warm light produced by living organisms. Chappelle developed a method using two chemicals, luciferase and luciferin, from fireflies which give off light when mixed with ATP (adenosine triphosphate), an energy storage compound found in all living cells, to detect the presence of ATP. This method for ATP detection can be used to detect life on other planets as well as microbiological organisms. Chappelle also proved that the number of bacteria in water can be measured by the amount of light given off by that bacteria. This discovery allowed scientists and doctors to detect small amounts of bacteria in places such as urine, in order to detect an onset of a bacterial infection. Additionally, he developed a method for determining vegetation health by using laser-induced fluorescence to measure the amount of photosynthesis occurring in crops, allowing scientists to detect plant stress, determine growth rates, water conditions, and harvest timing. Having achieved so much in his career, Chappelle retired from NASA in 2001, at the age of 76, and is now believed to live in Baltimore, Maryland with his daughter and son-in-law. Patents
References
9 : 1925 births|African-American inventors|African-American scientists|American biochemists|American inventors|Living people|Stanford University School of Medicine faculty|University of Washington alumni|University of California, Berkeley alumni |
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